1. Field
The present invention relates to a method of providing data relating to the aircraft intent of an aircraft using observations of the aircraft's trajectory. The inferred aircraft intent may be used for predicting the future trajectory of the aircraft, for use in conflict resolution within air traffic management, or for analyzing air traffic management.
2. Background
The ability to describe, and also to predict, an aircraft's trajectory is useful for many reasons. By trajectory, a four-dimensional description of the aircraft's path is meant. The description may be the evolution of the aircraft's state with time, where the state may include the position of the aircraft's center of mass and other aspects of its motion such as velocity, attitude and weight. In order to predict an aircraft's trajectory unambiguously, one must solve a set of differential equations that model both aircraft behavior and atmospheric conditions.
Aircraft intent is described using a formal language that describes how the aircraft is to be flown. The aircraft intent contains instructions that define aspects of motion and configuration of the aircraft. The aircraft intent contains sufficient information to allow an unambiguous determination of an aircraft's trajectory, i.e. the information that the aircraft intent contains closes all degrees of freedom of the aircraft's motion. The aircraft intent may be expressed as a series of instructions spanning part of a trajectory, with each instruction's length defining a flight segment. Each degree of freedom is described as a thread, and an instruction may operate on one or more threads. Thus, combinations of instructions may operate together to close all degrees of freedom of the aircraft.
The aircraft intent that comprises a structured set of instructions is used by a trajectory computation infrastructure to calculate the resulting unambiguous trajectory. As noted above, the instructions should include both configuration details of the aircraft (e.g. landing gear deployment) and procedures to be followed during maneuvers and normal flight (e.g. track certain turn radius or hold a given airspeed). These instructions capture the basic commands and guidance modes at the disposal of the pilot and the aircraft's flight management system to direct the operation of the aircraft. Thus, aircraft intent may be thought of as an abstraction of the way in which an aircraft is commanded to behave by the pilot and/or flight management system into a set of instructions that unambiguously capture the information and allow an unambiguous trajectory to be calculated.
EP patent application 07380259.7, published as EP-A-2,040,137, also in the name of The Boeing Company, describes aircraft intent in more detail, and the disclosure of this application is incorporated herein in its entirety by reference.
Knowledge of aircraft intent is useful in air traffic management. Knowledge of an aircraft's intent in advance allows accurate predictions of aircraft trajectories to be made that may be used to aid conflict detection and resolution. Furthermore, knowledge of aircraft intent after a trajectory has been flown may be of use in analyzing air traffic management, for example to assess how efficiently the air traffic management performs in areas such as fuel efficiency and noise performance. While aircraft intent data may be provided by the aircraft or the aircraft operator, aircraft intent data is not always readily available to other interested parties. In such situations, it may be useful for other interested parties to be able to obtain the aircraft intent in some other way.
Therefore, it would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above, as well as other possible issues.